Each day more than 200,000 United States Postal Service (USPS) carriers deliver mail to approximately 100 million individual domestic addresses. Each day, before a carrier begins to walk through or drive through his or her delivery route, it is the carrier""s responsibility to put all of this mail into an appropriate sequence for efficient delivery. Under the present USPS procedure, the carrier assembles at least three delivery order sequenced stacks of mail, including letters, flats (including enveloped and non-enveloped magazines), and parcels. As used herein xe2x80x9cletter sizedxe2x80x9d or xe2x80x9cletterxe2x80x9d generally refers to envelopes, postcards and similar mail pieces having dimensions up to about 5xe2x80x3xc3x9710xe2x80x3. xe2x80x9cFlatsxe2x80x9d as used herein generally refers to larger, flat mail pieces having dimensions larger than about 5xe2x80x3xc3x9710xe2x80x3, and includes catalogues, magazines, larger envelopes and similar items. At each delivery stop the carrier selects the items for that address from each of the various stacks and puts them all into the postal patron""s mailbox. This sorting and shuffling through various stacks of mail is time consuming, inefficient, and consequently expensive to the USPS. Consequently, any reduction in the number of sequenced stacks that have to be sorted and shuffled through during delivery represents the potential for increased efficiency.
To put mail in destination point order, a Delivery Bar Code Scanner (DBCS) and/or Carrier Sequence Bar Code Scanner (CSBCS) DBCS machine typically uses a multi-pass sorting scheme. Two and three pass schemes based on significant digits of the delivery points are most common. These known strategies are explained in detail in U.S. Pat. No. 5,363,971. In general, a multi-pass sort scheme starts with a disordered collection of mail having a common zip code and ends up with the same mail in a series of batches, one for each delivery point receiving mail. In order to accomplish the sort, intermediate batches of partially sorted mail are created that are then fed back into the sorter again for sorting according to a second pass sort scheme.
The result of this sorting process is, as noted above, multiple stacks of delivery ordered mail. In order to identify, for example, letters addressed to a specific address, the carrier xe2x80x9cthumbsxe2x80x9d through the stack, finding the first and last letter addressed to the address, separating the letters addressed to the address from the stack. This time consuming process is repeated with the stack of flats.
The invention set forth below provides a method of reducing the number of stacks that the letter carrier is required to go through and simplifies the process of separating mail pieces addressed to a specific destination from the stack.
A multi-pass sorting method for sorting mail pieces including both letter and flats and for delivery by a carrier, using a computer-implemented sort scheme includes the steps of: a) sorting in a first sorting pass a batch of letters, each letter having a destination code thereon which corresponds to one of a predetermined number of delivery destinations for a carrier delivery route, using an automated sorting machine which scans each delivery code and stores it in a computer memory, b) sorting in first sorting pass a batch of flats, each flat having a destination code thereon which corresponds to one of the predetermined number of delivery destinations for the carrier delivery route, using the same automated sorting machine which scans each delivery code and stores it in a computer memory, c) sorting in a first sorting pass a batch of dividers, one divider for each destination, and d) then sorting the letters, flats and dividers in at least one subsequent sorting pass, using the scanned and stored delivery codes according to the computer-implemented sort scheme, resulting in a series of groups of mail pieces for each destination, which groups may include letters only, flats only, or both letters and flats, and which groups are in delivery route order, with a divider between each group. The foregoing method creates a stack of mail in delivery order with dividers separating mail pieces destined for different addresses such that the carrier can readily and easily separate mail pieces for different destinations without the necessity of thumbing or shuffling though a stack of mail.
In an alternate variation, mail pieces destined for different destinations are separated with dividers only when adjacent mail pieces in the stack that are destined for different destinations or addresses are of the same type. In variation, after one or more initial passes using the scanned and stored delivery codes according to a computer-implemented sort scheme groups of mail pieces for each destination may include letters only, flats only, or both letters and flats in delivery route order. The groups containing letters only and flats only are then identified and in a final pass a divider is inserted between adjacent groups in the series whenever a group containing letters or flats only appears such that flats for one destination would otherwise be grouped consecutively with flats for another destination, or letters for one destination would otherwise be grouped consecutively with letters for another destination.
In yet another variation, the sequence into which the mail pieces will be sorted is determined during one or more initial passes through the sorter, and the locations in the stack where adjacent mail pieces of the same type are destined for delivery to different addresses are identified. In a final sort, a divider is inserted between adjacent mail pieces of the same type, for example two letter or two flats where the second mail piece is addressed to a different address than the first mail piece.
In another aspect the invention provides a method for sorting mail pieces for delivery by a carrier, wherein the mail pieces include both letters and flats, including the steps of a) sorting in a first sorting pass a batch of mail pieces, including letters and flats, each having a destination code thereon which corresponds to one of a predetermined number of delivery destinations for a carrier delivery route, using an automated sorting machine which scans each delivery code and stores it in a computer memory, and b) sorting in a subsequent pass the batch of mail pieces and a plurality of dividers using the scanned and stored delivery codes according to a computer-implemented sort scheme which results, after two or more sorting passes, in a series of groups of mail pieces for each destination, which groups may include letters only, flats only, or both letters and flats with a divider between adjacent groups. In this regard, the mail carrier may separate the individual groups as he or she conducts his route without shuffling or thumbing through stacks of mail to locate mail pieces addressed to a particular destination.